848
FXUS63 KLBF 252059
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
359 PM CDT Wed Sep 25 2024

.KEY MESSAGES...

- Elevated to near-critical fire weather conditions are forecast
  for portions of the Sandhills and eastern Panhandle on
  Thursday.

- Mild and dry conditions prevail through the 7-day forecast
  period, with recurring fire weather concerns through next
  week.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 358 PM CDT Wed Sep 25 2024

Broad ridge of high pressure aloft remains in place across the
Southern Rockies. Locally, amplified northerly flow is in place
across much of the Central and Southern Plains. Further downstream,
a cut-off low lists across the lower Ohio valley. This feature looks
to play a non-insignificant role in the progression of Hurricane
Helene of which no local impacts are expected.

Lee troughing will develop as a belt of enhanced flow crosses the
Northern Rockies. This surface trough will extend south into the
central High Plains late tonight. Ahead of this, a strong LLJ will
develop and overspread much of the area. This will likely lead to
fairly steady winds overnight. Did hedge overnight lows to the
warmer side of guidance, especially for locations outside sheltered
valleys. Can`t rule out some stronger gusts for the Sandhills and
closer to the Pine Ridge where speeds may exceed 20 mph and reach as
high as 30 mph for far northern Sheridan and northwestern Cherry
Counties. Thursday, the surface trough will push off the higher
terrain. As the day begins with another cloudless sky, boundary
layer mixing will begin in earnest and surface wind gusts will
quickly climb. Can`t rule out some gusts nearing 30 mph further east
towards Highway 83. Winds then begin to wane as the surface trough
moves into the far western Sandhills. In vicinity of this surface
trough, temperatures will quickly jump and utilized a mixture of
short-term guidance and higher percentile NBM values to bolster
inherited values slightly. This produced middle 90s for Cherry and
Sheridan County, with 80s to low 90s elsewhere. These values range
from 10-20 degF above normal for late September and even near 30
degF for the warmest locations previously mentioned. Low
temperatures Thursday night will be similar with lows falling into
the low 50s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 358 PM CDT Wed Sep 25 2024

Friday...A deeper northern stream disturbance will track east across
southern Canada late Thursday into Friday. While dynamics aloft will
remain well north of the area, an attendant cool front trailing the
parent low will drop down through the Northern and Central Plains.
This feature looks to enter western Nebraska early Friday. This
should bring with it a modest cooldown and slight increase in
atmospheric moisture. While this will likely not be enough to bring
precipitation chances, it should offset the threat for fire weather
concerns for a day.

Saturday and Sunday...mid-level heights look to recover with ridging
overspread the area once again. NAEFS climatology again advertises
upper-level heights exceeding the 90th percentile and at times
nearing the max in NAEFS ensemble guidance. Temperatures will
closely follow with values exceeding the 90th percentile across the
whole of the area by late weekend. Temperatures will return to
widespread upper 80s and lower 90s for the weekend. While winds
don`t appear to be problematic on Saturday, winds will increase on
Sunday ahead of a frontal boundary approaching from the north.
Steady southwesterly winds appear probable to gust upwards of 35 mph
across the Sandhills. This closely resembles NBM 25th Percentile
values, is more representative of of probabilistic guidance with
peak gusts exceeding 34 knots exceeding 80% for only the Pine Ridge
and quickly dropping to less than 50% outside the Sandhills.

Monday and beyond...as mentioned previously, a strong cool front
will drop through the area by early Monday. Precipitation potential
will be nil with PWATs nearing 0.50". Strong northerly winds in the
wake of this front will be the main change to sensible weather. NBM
probabilities of gusts exceeding 34 knots climb above 50% for all
locations and probabilities of exceeding 41 knots near 80% for much
of the Highway 20 corridor west of Valentine. While much cooler
temperatures will invade across the area, dry air will remain
plentiful and the expected strong winds may allow for fire weather
concerns to continue into the early work week. With similar highs in
the 60s and 70s for both Monday and Tuesday, similar fire weather
conditions will exist each day. Though winds look to decline some,
the going forecast still supports breezy conditions and elevated
fire concerns. Temperatures rebound around the middle of next week
but NBM guidance shows large spread in 25th and 75th percentile
values. This limits confidence somewhat though as upper-level
pattern details will need to be ironed out with subsequent
forecasts. What is more certain, however, is that our dry weather
stretch will likely prevail as ensemble guidance doesn`t show the
faintest bit of optimism regarding measurable rain until Tuesday as
the earliest and even this amounts to probabilities of less than 10%.
Both the EPS and GEFS model suites are in good agreement regarding
this. So the thought of fire weather concerns continuing through the
extended period is a fairly safe assumption at this time.


&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1220 PM CDT Wed Sep 25 2024

Expect clear skies at both the KLBF and KVTN terminals over the
next 24 hour period. Winds will be light from the south today
and tonight for the KVTN terminal and variable at under 10 KTS
for the KLBF terminal. After mid morning Thursday, look for
southerly winds to increase at both terminals with wind speeds
around 10 KTS at the KLBF terminal and 10 to 15 KTS at the KVTN
terminal. Wind gusts may approach 25 KTS at the KVTN terminal
around 18z Thursday.

&&

.FIRE WEATHER...
Issued at 358 PM CDT Wed Sep 25 2024

Elevated to near-critical fire weather conditions are expected for
much of western Nebraska on Thursday afternoon.

Temperatures near and ahead of a stalled surface trough will likely
climb above 90 degrees and near the upper 90s. These values are
generally 15 to 25 degF above normal. With little to no low-level
moisture, afternoon humidity values are expected to fall
precipitously into the lower teens for far northern Zone 204 and
western Zone 208. Elsewhere, values in the upper teens to 20s are
anticipated which remains above critical levels. The biggest caveat
about concerns on Thursday will be the winds. NWP guidance is in
good agreement on placing the stalled surface trough near a Kilgore
to Hyannis line. To the east of this, strong southerly gusts will
approach 20 to 25 mph. This will likely be a decrease from the
morning speeds when peak speeds may be closer to 30 to 35 mph. To
the west of the surface trough, general west-northwesterly flow will
be prevalent and speeds will be much more limited. This is signaled
by various hi-res guidance as well as deterministic solutions.
Forecast soundings near Gordon show deep mixing nearing 3km but
winds through the entire boundary layer remaining near 20 knots or
less. Because of these weaker winds where the lower humidity is
forecast, have opted to forego any fire weather headlines. Even so,
the stronger winds ahead of the surface trough will be favorable for
the spread of any fire starts.

Early next week, anomalous heat will remain in place ahead of a
stronger cool front set to dive south out of the Northern Plains.
Sunday and Monday will likely see near-critical fire weather
concerns once again owing to strong winds and low afternoon
humidity. Winds flip behind the frontal passage early Monday with
strong northerly winds. Though temperatures will likely cool
slightly, dry air will again be the norm and likely lead to
afternoon humidity values bottoming out around 20%. Some questions
linger about potential cloud cover perhaps hampering insolation and
how far humidity falls but probabilistic guidance continues to
support at least an elevated mention given the expected strong
winds. Similar conditions exist Tuesday before a return to well
above normal temperatures around the middle of the week favor lower
humidity but weaker winds.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...NMJ
LONG TERM...NMJ
AVIATION...Buttler
FIRE WEATHER...NMJ